CPPD vs Gout



== CPPD == 



Think About CPPD When:

 • Self-limited synovitis after surgery/trauma (> 65 years old)

 • Unilateral swelling in weird joints (shoulders, wrists, elbows)

 • Underlying disease states



Pathophysiology:

 • Pyrophosphate produced by chondrocytes likely precipitates with calcium to form CPP crystals, which then deposit and can activate inflammatory pathways, resulting in an acute arthritic flare.



1. Asymptomatic CPPD:

Cartilage calcification appears as a linear opacity below the surface of articular cartilage

2. Acute CPP Crystal Arthritis:

Monarticular inflammatory arthritis, characterized by sudden onset of swelling, pain, loss of function, tenderness, and warmth

3. Chronic CPP Crystal Inflammatory Arthritis:

Resembles RA

4. Osteoarthritis with CPPD:

OA in atypical locations: Wrist, MCP, or shoulder joints



Think of the "H's" Especially if < 50 Years Age:

 • Hemochromatosis

 • Hyperparathyroidism

 • Hypothyroidism

 • Hypomagnesemia



Synovial Fluid:

 • WBCs >2000-100,000/µL; neutrophil predominance

 • CPP crystals

     • Rhomboid shaped

     • Weakly positively birefringent or not birefringent

 • Gram stain, culture used to diagnose concomitant infection

 • Imaging may show chondrocalcinosis



== Gout == 



3 Conditions for Gout to Manifest:

1. Hyperuricemia

2. Monosodium urate deposition in joints and/or soft tissues

3. A reaction to phagocytosed crystals that leads to an acute inflammatory response



Risk Factors:

 • Advanced age

 • Male sex

 • Metabolic syndrome

 • Medications (diuretics)



Epidemiology:

 • Men in 4th to 5th decade

 • Postmenopausal women



Presentation:

1. Acute Intermittent Gout:

	• Great toe (podagra): 50% of initial attacks

	• Other joints include forefoot, ankles, knees, fingers, wrist, elbow

	• Nocturnal onset --> Peak 12-24 Hours

	• Fever, erythema, swelling, significant pain

2. Intercritical Gout: Asymptomatic period between attacks



Gout: Synovial Fluid Testing:

 • WBCs >2000-100,000/µL; neutrophil predominance

 • Urate crystal - Needle-shaped, negatively birefringent

 • Acute gout - Intracellular (leukocyte) crystals

 • Intercritical gout - Extracellular crystals

 • Gram stain and culture- Diagnose concomitant infection



Serum Urate Levels:

 • Not helpful in acute gout

 • ↑ C-reactive protein, ESR, leukocytosis

 • Nonspecific findings



#CPPD #Gout #Comparison #rheumatology #Diagnosis